acoustic test setup at south pole
DESCRIPTION
Acoustic test setup at south pole. IceCube Collaboration Meeting, Berkeley, March 2005. Motivation. Evalution of acoustic detection needs acoustic parameters of south polar ice. Absorption length ≈ few km temperature dependant depth dependant Speed of sound / refraction - PowerPoint PPT PresentationTRANSCRIPT
Sebastian Bö[email protected]
Acoustic test setup at south pole
IceCube Collaboration Meeting,
Berkeley, March 2005
Acoustic test setup at pole – 2 [email protected]
Motivation
Absorption length ≈ few km temperature dependant
depth dependant
Speed of sound / refraction vice ≫ vwater
larger signals ( Pmax ∞ vice2 )
density dependant refraction of surface noise
Noise level determines energy threshold
Background events few signal events/year
few transient events or good suppression
Evalution of acoustic detection needs acoustic parameters of south polar ice
Acoustic test setup at pole – 3 [email protected]
Setup
Use IceCube 3 distant holes down to 400 m
7 levels per hole sensors transmitters auxiliary
Surface digitization String PCs
DAQ Power Fiber LAN
Acoustic test setup at pole – 4 [email protected]
Acoustic stageIn all three holes
at the same height do measurement in same layer
sensor and transmitter at each stage reduce systematic error in redundant setup
Sensor module and transmitter module close together check with low signals standard pressure housing
10 cm diameter steel tube end caps with commercial penetrators
String support own steel cable avoid signal shielding by IceCube cable
need spacer
Auxiliary devices temperature or pressure senors commercial hydrophones
Acoustic test setup at pole – 5 [email protected]
Acoustic stage: sensor
Sensor module based on existing design PZT5 piezoceramics plus
amplifier directly coupled to steel tube
three channels per module local coincidences directional information
Power supply cable losses
use larger supply voltage
±5V generated in module
Acoustic test setup at pole – 6 [email protected]
Acoustic stage: transmitter
Active element piezoceramic transducer
signals ≥ 1000 V possible no orientation possible
ring-shaped ceramic azimuthal symmetry
broad resonance large pressure amplitude
directly coupled to the ice calculable system
HV Signals Problem: cable capacitance
down in the ice use LC-circuits
sine bursts and pulses
Acoustic test setup at pole – 7 [email protected]
Cables
Option 1: flexible outdoor robot cable 6×2, 8×2 … 16×2 twisted pairs 0.51 mm2 (ATW24), 100 Ohm
loss: < 2 dB/100m used for moving parts at -40 deg
≈ 6 € / m (8×2 one cable)
Sensors differential signals
3×2 (twisted pairs) power supply
1×2
Option 2: use cheap ethernet cables 4×2 twisted pairs 0.52 mm2 (ATW24), 100 Ohm
loss: < 2 dB/100m two free pairs from transmitter
use for auxiliary sensors tested for -20 deg
test at lower temperatures
≈ 0.3 € / m (4×2 two cables)
Transmitters signal
1×2 power supply
1×2
Acoustic test setup at pole – 8 [email protected]
String PC
Limitations cable costs cable losses
DAQ at top of each string
String PC DAQ board(s) Power supply Fiber LAN switch only used for data handling
slow CPU, small disk buried in snow
waterproof container
Acoustic test setup at pole – 9 [email protected]
String PC: DAQ
DAQ requirements Low sampling rates low data rates
use of the shelf DAQ
Proposal: NI-DAQ 6259 16 differential inputs
two cards per strings 1.25 MHz single channel 1.0 MHz multichannel
83.3 kHz per channel digital and analog triggering variable gain: ± 50 mV to ± 10 V
large dynamic range 4 differential outputs
transmitter signals
Acoustic test setup at pole – 10 [email protected]
String PC: Power supply
Power consumption Wire resistance: AWG24 (0.5mm2), 500m
86 ohm / pair
Sensor ± 5V / 30mA per amplifier
~ 1W / 100mA per module cable loss (86ohm, 0.1A) ΔU = 8.6V
Transmitter +5V / 200mA,
~ 1W per module cable loss (86ohm, 0.2A) ΔU = 17.2V
Power Supply: TXL Series Uin = 86V-264 VAC 50/60Hz size 99x82x35 mm
fits into standard PC housing sensors: TXL 035-1515D
Uout = ±15V / 1.3A transmitters: TXL Series, TXL 060-24S
Uout = 24V / 2.5A
Total: ~15 W per string
Acoustic test setup at pole – 11 [email protected]
Cost estimate
Item Quantity Cost Total
Sensor modules 21 200,- € 4.200 €
Transmitter modules 21 300,- € 6.300 €
Auxiliary sensors (temperature, pressure,…) 21 10,- € / ? 210 €
Sensor cables 4.440 m ≈ 3,- €/m ≤ 15.000 €
Transmitter cables 4.440 m ≈ 3,- €/m ≤ 15.000 €
Master PC 1 2.000,- € 2.000 €
String PC 3 1.000,- € 3.000 €
DAQ card 6 1.195,- € 7.170 €
Power supply 6 50,- € 300 €
Fiber LAN switch (String PC) 3 500,- € 500 €
Fiber LAN switch (Master PC) 1 1.000,- € 1.000 €
Waterproof PC container 3 500,- € 1.500 €
PC Power cable ≤ 1000 m 2,- €/m 2.000 €
Fibre LAN cable ≤ 1000 m 2,7 €/m 2.700 €
Total sum 60.880 €
Acoustic test setup at pole – 12 [email protected]
Project schedule 2005
April May June July August September October
WK 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44
Sensor finalization
Sensor and transmitter building
Sensor and transmitter calibration Setup
whole systemBuild DAQ system
Test system in lake
DAQ software developement
Software testing
Order parts
Parts arrive
Ship to pole
Acoustic test setup at pole – 13 [email protected]
Constraints from IceCube
Cargo cables, PCs, DAQ Sensor and transmitter modules
total cargo need ≤ 5m3
Manpower deployment: trained person
at the spot commissioning: DAQ connection
and setup, primary testing one person, two weeks
Deployment separate deployment deployment with string possible
only affecting the last 400 m OMs are in safe depth
find best solution with IceCube deployment responsibles
Interference with IceCube Acoustic signals
1 km above IceCube < 10 mPa signal at OMs
Electric signals low voltage (±5Vpp)
High voltage generated localy low duty cycle (≤ 1%).
DAQ, power supply seperate from IceCube
no interference expected
Acoustic test setup at pole – 14 [email protected]
Summary
all components are available and tested
reasonable cost and time scale
! major activities at all other neutrino telescopes
go for pole season 05/06